Commitments and Contingencies - Summary of Operating Leases for Office and/or Manufacturing Space (Detail)	12 Months Ended
	Apr. 30, 2017
Wilsonville | Oregon
Schedule Of Commitments And Contingencies [Line Items]
Lease Expiration Date	Oct. 31, 2017
Scottsdale | Arizona
Schedule Of Commitments And Contingencies [Line Items]
Lease Expiration Date	Feb. 28, 2018
Somersworth | New Hampshire
Schedule Of Commitments And Contingencies [Line Items]
Lease Expiration Date	Jun. 30, 2018
Bentonville | Arkansas
Schedule Of Commitments And Contingencies [Line Items]
Lease Expiration Date	Sep. 25, 2018
Jacksonville | Florida
Schedule Of Commitments And Contingencies [Line Items]
Lease Expiration Date	Dec. 31, 2018
Columbia | Missouri
Schedule Of Commitments And Contingencies [Line Items]
Lease Expiration Date	Apr. 30, 2023
Deep River | Connecticut
Schedule Of Commitments And Contingencies [Line Items]
Lease Expiration Date	May 04, 2024